Problem: $\dfrac{5}{6} - \dfrac{4}{8} = {?}$
Answer: $ = {\dfrac{5 \times 4}{6 \times 4}} - {\dfrac{4 \times 3}{8 \times 3}} $ $ = {\dfrac{20}{24}} - {\dfrac{12}{24}} $ $ = \dfrac{{20} - {12}}{24} $ $ = \dfrac{8}{24}$